Water-based delivery systems

ABSTRACT

The invention relates to a water-based delivery system for an active substance, characterized by enhancing skin barrier restoration in the stratum corneum comprising water, a fatty acid, cholesterol, a ceramide and at least one skin lipid precursor.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 60/365,059, filed Mar. 13, 2002, which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a novel topical and mucosal delivery systems for drugs or any other active substance.

BACKGROUND OF THE INVENTION

The main demands on human skin are to prevent loss of water, and to prevent water and other matter of the environment from entering the body indiscriminately. The human skin thus forms a selectively permissible physical barrier between the human body and its surroundings.

The barrier function has been shown to reside in the stratum corneum. The stratum corneum is the topmost layer of the skin, and is built of corneocytes. Corneocytes are cells that contain extensively cross-linked proteins, surrounded by a highly resistant cell envelope. The corneocytes are embedded in a bed of specific lipid structures of long chain lipids. These long chain lipids are organized as bilamellar structures stacked on top of each other. The bilamellar structures fill the intercellular spaces between the corneocytes.

To account for the skin's barrier properties, and for its selective hydrophilic and hydrophobic pathways, the skin has been described as a mosaic barrier model. This model envisages barrier lipids to exist predominantly in crystalline (gel) form. Such a form provides water impermeable domains, which are surrounded by so-called grain borders of lipids in a liquid crystalline state. This arrangement provides an effective, water tight barrier that still allows a minute but controlled loss of water through the liquid crystalline interdomains. This controlled water loss is enough to keep the keratin of the stratum corneum hydrated. The liquid character of the interdomain grain borders allows passage of hydrophilic and hydrophobic molecules on down-hill gradients, i.e. passage by passive diffusion.

Dermal delivery systems are compositions which deliver active substances to, or through, the skin. These compositions typically contain skin permeation enhancers. Permeation enhancers may induce structural transformations of the bilamellar structure in the liquid crystalline interdomain regions, and thus promote transdermal delivery of, for example, pharmacological substances.

Typical dermal delivery systems have an alcohol or petroleum base, with little consideration given to the biological properties of the vehicle itself. For example, emulsified fatty acids can inherit certain detergent properties if their structure is significantly altered from those in the normal skin. The detergent properties can lead to disruption of the normal barrier function, which is counteractive to the potential benefit of the delivery system. Disruption of the normal barrier function often causes the stratum corneum to lose its natural potential to function properly as a barrier. As a result, the skin becomes either too dry or too permeable to environmental substances.

Other conventional delivery systems that are thought to protect the skin from harmful substances are barrier ointments. The purpose of barrier ointments is to provide a film, and thereby create a layer which is impermeable to environmental substances. Due to the impermeability, though, these ointments both increase the body temperature of the treated body part, as well as prevent perspiration, and thus render an uncomfortable sensation.

The dermal delivery systems described above are not formulated to deliver a substance to, or through, the human skin without permanently disrupting the stratum corneum's natural barrier function.

SUMMARY OF THE INVENTION

In one embodiment, the invention relates to a water-based delivery system for an active substance, characterized by enhancing skin barrier restoration in the stratum corneum comprising water, a fatty acid, cholesterol, and a ceramide. In another embodiment, the delivery system also comprises at least one skin lipid precursor.

In an additional embodiment, the invention relates to delivery system for an active substance comprising water and lipophilic components, wherein the lipophilic components comprise fatty acids, cholesterol, and a ceramide/phospholipid portion, and wherein the lipophilic components are in the form of lipid particles, and gas spheres or vesicles. This delivery system can also comprise at least one skin lipid precursor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing the gas spheres, lipid particles, vesicles and hydrophilic phase of the delivery systems.

FIG. 2 is a diagram showing the components of the gas spheres of the delivery systems.

FIG. 3 is a diagram showing the components of the lipid particles and of the vesicles of the delivery systems.

FIG. 4 is a diagram showing the location of active substances within the various microcompartments of the delivery systems.

DETAILED DESCRIPTION OF INVENTION

The present invention provides an improved topical delivery system (skin preparation) formulated to deliver a substance to, or through, the human skin without permanently disrupting the stratum corneum's natural barrier function. Additionally, the topical delivery system of the present invention provides unique skin barrier restoration properties.

All percentages given below are indicated in percent by weight. All numbers are approximate.

The topical delivery system of the present invention is a water-based formulation comprising hydrophilic and lipophilic components. In a preferred embodiment, the delivery system comprises a water content exceeding 50%, such as more than 55%, 60%, 65%, 70%, 75%, 76%, 77%, 78%, 79%, 80%, 85%, 87%, 90%, 94%, 95% and 98%. Preferably, the water content is between 60-80%, more preferably, between 70 and 80%.

The topical delivery system is preferably designed, in its choice and composition of lipids, to resemble the normal lipid organization of the stratum corneum (horny layer), as much as possible. Upon administration, the system (formulation) blends with the lipids naturally present in the stratum corneum, and easily penetrates the lipid bilayer of the skin. In doing so, the system carries along with it one or more active substances to be administered. The system enhances penetration of active substances into and/or through the stratum corneum, while the normal barrier properties of the stratum corneum are left intact, and/or are even functionally enhanced.

The lipophilic component (i.e. lipids) of the system comprises fatty acids, cholesterol and a ceramide/phospholipid portion. The lipids are similar to those which make up the normal stratum corneum. The preferred ratio of the ceramide/phospholipid portion:cholesterol:fatty acid is in the range of approximately 2:1:1.5 to approximately 2.95:0.5:0.5. Preferably, for example, the ratio is approximately 2:1:1; more preferably the ratio is approximately 2.35:1:1.

The fatty acids of the present invention can be any fatty acid, mixtures of fatty acids, salts of fatty acids, or mixtures of fatty acids and salts of fatty acids. The fatty acids can be saturated or unsaturated. Additionally, the fatty acids can comprise precursors of fatty acids. In a preferred embodiment, the fatty acids comprise ten, twelve, fourteen, sixteen, eighteen, twenty, twenty-two, or twenty-four carbon atoms, or any mixture of such fatty acids. A fatty acid mixture with a predominant portion of fatty acids which comprise a chain of sixteen or eighteen carbon atoms is most preferred.

For example, the delivery system can be prepared from a mixture of fatty acids of the following composition: at most about 2% of a component comprising a chain of fourteen carbon atoms, between about 47 and about 52% of a component comprising a chain of sixteen carbon atoms, between about 43 and about 48% of a component comprising a chain of eighteen carbon atoms, and at most about 1% of a component comprising a chain of twenty carbon atoms.

Examples of suitable saturated fatty acids for use in the delivery system include lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, and lignoceric acid. Examples of suitable unsaturated fatty acids include oleic acid, palmitoleic acid, linoleic acid, linolenic acid, and arachidonic acid. Preferably, the delivery system contains an essential portion, such as about 90%, of such fatty acids.

The preferred fatty acids are the essential fatty acids (EFAs). EFAs are essential for the plasma membrane formation of all cells. In keratinocytes, EFA deficiency makes cells hyperproliferative. Supplementation of EFAs reverses the hyperproliferation. EFAs also enhance lipid biosynthesis of the epidermis and provide lipids for the barrier formation of the epidermis. The essential fatty acids are preferably chosen from linoleic acid, γ-linolenic acid, homo-γ-linolenic acid, columbinic acid, eicosa-(n-6,9,13)-trienoic acid, arachidonic acid, timnodonic acid, hexaenoic acid, and mixtures thereof.

The delivery system also comprises cholesterol, or derivatives of cholesterol such as, for example, lipid esters of cholesterol.

The ceramide/phospholipid portion can comprise 100% ceramide, 100% phospholipids, or any other percent combination of ceramide and phospholipids. For example, the ceramide/phospholipid portion can comprise 95% ceramide and 5% phospholipids, 90% ceramide and 10% phospholipids, 85% ceramide and 15% phospholipids, or 80% ceramide and 20% phospholipids.

The ceramide component of the delivery system can be any ceramide or any mixture of ceramides. In this specification, ceramides include pseudoceramides and neoceramides.

For example, the ceramide may be any of ceramide 1-7; and/or mixtures thereof. Some specific examples of ceramides include ceramide 1, ceramide 3, ceramide 4, ceramide 5, ceramide 6A, cerebrosides and ceramide 6B.

Some examples of pseudoceramides include:

-   N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)hexadecanamide -   N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)propanamide -   N-(2-hydroxyhexadecyl)-N-(2-hydroxyethyl)butanamide -   N-(2-hydroxyhexadecyl)-N-(2-hydroxyethyl)heptanamide -   N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)ethanamide -   N-(2-hydroxyoctadecyl)-N-(2-O-glucopyranosyl)ethylpentanamide -   N-(2-hydroxydodecyl)-N-(2-hydroxyethyl)hexanamide -   N-(2-hydroxydodecyl)-N-(2-hydroxyethyl)-2butylhexanamide -   N-(2-hydroxyhexadecyl)-N-(2-hydroxyethyl)ethanamide -   N-(2-hydroxydodecyl)-N-(2-hydroxyethyl)-2-hydroxyhexanamide -   N-(2-hydroxytetraadecyl)-N-(2-hydroxyethyl)propanamide -   N-(2-hydroxyhexadecyl)-N-(2-sulfoethyl)hexadecanamide -   N-(2-hydroxyoctadecyl)-N-(2-phosphoethyl)butanamide -   N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)-2-hydroxypropanamide -   N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)hexadecanamide -   N-(2-hydroxy-3-nonanyloxypropyl)-N-(2-hydroxyethyl)propanamide -   N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)-2-hydroxypropanamide -   N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-hydroxyethyl)hexadecanamide -   N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)butanamide -   N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-hydroxyethyl)ethanamide -   N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-sulfohydroxyethyl)decanamide -   N-(2-hydroxy-3-decyloxypropyl)-N-(2-hydroxyethyl)hexanamide -   N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)hexadecanamide -   N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)butanamide -   N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)co-o-linoleoyldocosanamide -   N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)propanamide -   N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-hydroxyethyl)-2-methylpropanamide -   N-(2-hydroxy-3-tetraadecyloxypropyl)-N-(2-hydroxyethyl)ethanamide -   N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)heptanamide -   N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-phosphoethyl)hexadecanamide -   N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)propanamide -   N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-)-glucopyranosyl)ethyl-2-hydroxypropanamide -   N-(2-hydroxy-3-octyloxypropyl)-N-(2-hydroxyethyl)pentanamide     Some examples of neoceramides include: -   N-(2,3-dihydroxypropyl)-N-(hexadecyl)butanamide -   N-(2,3-dihydroxypropyl)-N-tetradecyl)ethanamide -   N-(2,3-dihydroxypropyl)-N-(hexadecyl)-2-hydroxypropanamide -   N-(2,3-dihydroxypropyl)-N-(octadecyl)butanamide -   N-(2,3-dihydroxypropyl)-N-(2-ethylhexadecyl)hexanamide -   N-(2,3-dihydroxypropyl)-N-(hexadecyl)-2-hydroxyoctanamide -   N-(2,3-dihydroxypropyl)-N-(3-methylhexadecyl)ethanamide -   N-(2,3-dihydroxypropyl)-N-(dodecyl)butanamide -   N-(2,3-dihydroxypropyl)-N-(hexadecyl)-2-hydroxyhexanamide -   N-(2-hydroxy-3-O-glucopyranosylpropyl)-N-(hexadecyl)octanamide -   N-(2-hydroxy-3-phosphopropyl)-N-(octadecyl)ethanamide -   N-(2-hydroxy-3-sulfopropyl)-N-(hexadecyl)butanamide -   N-(2-hydroxy-3-O-glucopyranosylpropyl)-N-(hexadecyl)decanamide -   N-(2,3-dihydroxypropyl)-N-(heptadecyl)ethanamide -   N-(2,3-dihydroxypropyl)-N-(3-methylhexadecyl)ethanamide -   N-(2,3-dihydroxypropyl)-N-(heptadecyl)butanamide -   N-(2,3-dihydroxypropyl)-N-(6-dodecenyl)hexadecan-amide -   N-(2,3-dihydroxypropyl)-N-(2-methylhexadecyl)-2-hydroxy-ethanamide -   N-(2,3-dihydroxypropyl)-N-(octadecyl)-2-hydroxypropan-amide -   N-(2-hydroxy-3-O-glucopyranosylpropyl)-N-(heptadecyl)-ethanamide -   N-(2-hydroxy-3-sulfopropyl)-N-(dodecyl)heptanamide -   N-(2,3-dihydroxypropyl)-N-(tetradecyl)-4-hydroxybutanamide -   N-(2,3-dihydroxypropyl)-N-octadecyl)-(t)-O-linoleoyl-docosanamide -   N-(2,3-dihydroxypropyl)-N-(linoleyl)ethanamide -   N-(2,3-dihydroxypropyl)-N-(oleyl)-2-hydroxy-heptan-amide -   N-(2,3-dihydroxypropyl)-N-iyiodecyl)-(t)-O-linoleoyidocosanamide -   N-(2,3-dihydroxypropyl)-N-(octadecyl)-3-hydroxybutanamide -   N-(2-phospho-3hydroxypropyl)-N-(heptadecyl)butanamide -   N-(2,3-dihydroxypropyl)-N-(2-methylheptadecyl)propanamide -   N-(2,3-dihydroxypropyl)-N-(3-ethylheptadecyl)butanamide -   N-(2-sulfo-3-hydroxypropyl)-N-(1-octadecyl)ethanamide -   N-(2,3-dihydroxypropyl)-N-(octadecyl)propanamide -   N-(2,3-dihydroxypropyl)-N-(dodecyl)decanamide -   N-(2,3-dihydroxypropyl)-N-(3-ethyldodecyl)butanamide -   N-(2-O-glucopyranosyl-3-hydroxy propyl)-N-(heptadecyl)butanamide -   N-(2,3-dihydroxypropyl)-N-(oleyl)-2-hydroxypropanamide -   N-(2,3-dihydroxypropyl)-N-(linoleyl)-2-hydroxyheptanamide -   N-(2,3-dihydroxypropyl)-N-dodecyl)-2-hydroxyoctanamide -   N-(2,3-dihydroxypropyl)-N(hexadecyl)-2-methylheptanamide -   N-(2,3-dihydroxypropyl)-N-(octadecyl)-2-hydroxypentanamide -   N-(2,3-dihydroxypropyl)-N-(2-methylhexadecyl)-2-hydroxyheptanamide -   N-(2,3-dihydroxypropyl)-N-(linoleyl)-2-hydroxypropanamide -   N-(2; 3-dihydroxypropyl)-N-(tetradecyl)ethanamide.

The phospholipid component may contain any phospholipid or mixtures of phospholipids. Preferably the phospholipid component comprises phosphatidycholine (PC). Other examples of phospholipids include distearoylphosphatidylcholine (DSPC 18), phosphatidic acid, inositol phosphate, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, and phosphatidylethanolamine.

Additionally, the phospholipid component can comprise one or more lysophospholipids. Lysophospholipids are single chain phospholipids. Examples of lysophospholipids include lysophosphatidylcholines, such as monopalmitoylphosphatidylcholine (MPPC); lysophosphatidylglycerols; lysophosphatidylethanolamines; lysophosphatidylinositols; lysophosphatidylserines; and lysophosphatidic acid. Mixtures of different types of phospholipids and/or lysophospholipids can also be used.

In a preferred embodiment, the present system also comprises skin lipid precursors. The lipid precursors include any compound that promotes in situ cholesterol, ceramide or sphingolipid synthesis. The preferred lipid precursors are mevalonic acid, which promotes in situ cholesterol synthesis; and 25-hydroxycholecalciferol, which promotes in situ ceramide synthesis in the skin. Other preferred precursors are palmitoyl CoA and serine, which together are converted to 3-ketosphinganine, which promotes in situ ceramide synthesis in the skin.

By the promotion of in situ cholesterol and ceramide synthesis in the skin, the overall content of lipid in the system can be maintained in a range as low as approximately 2-20%. Therefore, the water content of the delivery system can be as high as 80-98%. The high water content enables the skin to “breathe” normally, and enhances its ability to restore its normal barrier function rapidly.

Other lipid precursors useful in the present invention include, for example: acylceramides; deoxyacetein cimifugoside, adapalene, adenosine, aloe derived lectins, 3-aminopropyl dihydrogen phosphate, anise extracts, ascorbic acid and derivatives thereof, ascorbyl palmitate, asiatic acid, benzoic acid derivatives, biotin, butanoyl betulinic acid, cathecholamines, coenzyme Q10, dehydrocholesterol, dehydroascorbic acid and derivatives thereof, estrogen and derivatives, eythrobic acid, genistein, lipoic acid, 4-methoxysalicylic acid, N-acetylcysteine, panthetine, pregnenolone and derivatives, retinal, retinoates, retinal, retinyl acetate, retinyl glucuronate, retinyl linoleate, retinyl palmitate, retinyl proprionate, phytosphingosine, sphingosine, and others.

Preferably, an alkaline compound, or buffer system, is included in the formulation to adjust the pH. Examples of alkaline compounds include triethanolamine (TEA), sodium hydroxide, sodium acetate, and sodium bicarbonate. Examples of buffer systems include carbonic acid/potassium carbonate, phosphoric acid/potassium phosphate, and acetic acid/sodium acetate.

The fatty acids of the final delivery system can be in a free state or can form a salt. The portion of fatty acids which is in a free state is partially dependent on the pH of the formulation. In general, the level of free fatty acid increases as the pH of the formulation decreases. Depending upon the particular use of the formulation, the pH of the formulation can vary. Preferably, the pH of the formulation is about 6.5 to 7.8.

In a preferred embodiment, the delivery system comprises triethanolamine (TEA). It is preferred to adapt the molar ratio between the fatty acids and triethanolamine to enable a certain portion of the fatty acids in the final delivery system to form a triethanolaminium salt, while another portion of the acid exists as free fatty acid. Preferably, the delivery system is prepared from fatty acids and triethanolamine in which the molar ratio of the fatty acids to the triethanolamine is higher than about 2:1, preferably higher than about 3:1.

In a preferred embodiment, the delivery system comprises a combined content of a fatty acid, cholesterol, a ceramide/phospholipid portion, and skin lipid precursors between about 2-20%. A preferred low end of this range is about 2%, 3%, 4%, 5%, 6%, 7% or 8%. A preferred high end of this range is about 13%, 14%, 15%, 16%, 17%, 18%, 19% and 20%.

In another preferred embodiment, the amounts of the components of the delivery system are as follows: fatty acid: 0.5-10%; cholesterol: 0.5-10%; a ceramide/phospholipid portion: 0.005-20%; and lipid precursors: 0.000001-10%.

In a preferred embodiment, the formulation does not contain any irritating ingredients. Examples of irritating ingredients include alcohols, such as isopropanol and ethanol; short chain fatty acids; and detergents. Preferably, the formulation contains less than 10% alcohol, more preferably less than 5% alcohol, most preferably less than 1% alcohol, and optimally no alcohol.

Without the intention to limit the scope of the invention, a possible theory explaining the mechanical properties of the delivery system follows. The administered formulation easily penetrates the lipid bilayer of the skin. In doing so, the system creates a temporary and reversible state of enhanced atrophy among the lipid components of the bilayer. The enhanced atrophy in itself then gives rise to either a) enhanced energy levels, wherein the energy could promote active transport of the to-be-carried substances into the skin, and/or b) creates naturally and reversibly occurring holes and disorganized patches in the lipid bilayer through which the active substances could then pass more easily. It is very well feasible that the temporary disarray in the lipid bilayer will temporarily break up the organized structure of the bilayer and create micelles of lipids with areas between them, or surrounding them, through which lipophobic/hydrophilic substances and/or compositions can enter through the stratum corneum. As the lipid composition of the formulation resembles the natural lipid composition of the skin, the so introduced new lipids will after a short time of creative chaos easily blend in with the natural lipid building stones of the lipid bilayer, and thus not permanently damage the barrier function of the skin.

Following the temporary disarray in the lipid bilayer, the normal barrier function of the cornea stratum rapidly returns. (That is, the skin barrier restoration is rapid.) The rapid return may be enhanced by the lipid precursors of the formulation. For example, the in situ promotion of cholesterol synthesis in the stratum corneum, the in situ promotion of ceramide synthesis in the stratum corneum, and/or the in situ promotion of sphingolipid synthesis in the stratum corneum may allow for the rapid skin barrier restoration.

A delivery system according to the present invention preferably comprises a combination of:

Fatty Acid (C16-24) 0.5-10% Phospholipid 0.5-10% Cholesterol 0.5-7%  Lipid precursor: 0.000001-10%    Mevalonic acid and/or 25-Hydroxycholecalciferol Ceramide 0.005%-7%      (Not all components are present are 0%.) Another preferred embodiment of the delivery system comprises:

Fatty Acid (C16-24) 0.5-10% Phospholipid 0.5-10% Cholesterol 0.5-7%  Lipid precursor: 0.000001-10%    Mevalonic acid and/or 25-Hydroxycholecalciferol Ceramide 0.005%-7%      Glycerine  0-5% Propylene glycol   0-48% PVP (e.g., M weight 40.000)  0-5% TEA  0-3% (Not all components are present are 0%.) An even more preferred embodiment of the delivery system comprises:

Fatty Acid (C16-24) 2% Phospholipid 4.5%   Cholesterol 2% Lipid precursor: 0.000001-10% Mevalonic acid and/or   1% or 0.01% 25-Hydroxycholecalciferol 0.015% or 0.0015% Ceramide 3 0.015%    Glycerine 3% Propylene glycol 4% PVP (M weight 40.000) 2% TEA 0.5%   An even more preferred embodiment of the delivery system comprises:

Fatty Acid (C16-24) 2% Phospholipid 4.5%   Cholesterol 2% Lipid precursor: 0.000001-10% Mevalonic acid and/or   1% or 0.01% 25-Hydroxycholecalciferol 0.015% or 0.0015% Ceramide 3 0.015%    Glycerine 3% Propylene glycol 4% PVP (M weight 40.000) 2% TEA 0.5%   Ceramide 1 0.025%   

The topical delivery system according to the present invention further comprises one or more cosmetically and/or therapeutically active substances. Active substances are defined as agents other than emollients and other than ingredients that merely improve the physical characteristics of the formulation.

Some general examples of active substances include sunscreens, tanning agents, skin anti-wrinkling agents, anti-dandruff agents, anti-acne agents, hair growth stimulants and vitamins. Therapeutically active substances include, but are not limited to, substances which treat conditions such as eczema, dry skin, itchy skin, fungal infection, acne, skin cancer, hair loss, louse infection, psoriasis, and skin lesions (i.e. wounds). Therapeutically active substances also include substances for transdermal delivery, for example, interleukin, hormones, vaccines, nicotine, interferon, pain killers, peptides, proteins and vitamins.

Active substances also include steroid hormones. Steroid hormones inhibit inflammation and hyperproliferation of the epidermis thus resulting in normalization of hypersensitive skin conditions. Examples of steroid hormones include, bat are not limited to, glucocorticoids, androgens and estrogens.

Examples of sunscreens include those materials commonly employed to block ultraviolet light. Illustrative compounds are derivatives of PABA, cinnamate and salicylate. For example, octyl methoxycinnamate and 2-hydroxy-4-methoxybenzophenone (also known as oxybenzone) can be used. Octyl methoxycinnamate and 2-hydroxy-4-methoxybenzophenone are commercially available under the trademarks, Parsol MCX and Benzophenone-3, respectively. The exact amount of sunscreen employed in the systems can vary depending upon the degree of protection desired from the sun's UV radiation.

Examples of vitamins include vitamin A and vitamin E, preferably in the form of an ester of a fatty acid, such as vitamin A palmitate (retinyl palmitate) and vitamin E linoleate (tocopheryl linoleate). Other esters of vitamins A and E may also be utilized, such as any of the fatty acids mentioned above and below.

Preservatives may also be included in the formulations of the present invention. Suitable preservatives include alkyl esters of p-hydroxybenzoic acid, hydantoin derivatives, propionate salts, and a variety of quaternary ammonium compounds. Particularly preferred preservatives of this invention are methyl paraben, propyl paraben, imidazolidinyl urea, sodium dehydroxyacetate and benzyl alcohol. Preservatives are typically used in amounts up to about 2% by weight of the formulation.

Other adjunct minor components may also be incorporated into the formulations of the present invention. These components may include thickeners, coloring agents, opacifiers and perfumes. For example, any thickening agent can be included in the formulation to adjust the viscosity of the formulation. Examples of suitable thickening agents include glycerol and xanthan gum. Some additional adjunct minor components include chalk, talc, Fullers earth, kaolin, starch, smectites clays, chemically modified magnesium aluminium silicate, organically modified montmorillonite clay, hydrated aluminium silicate, fumed silica, aluminium starch octenyl succinate and mixtures thereof. Amounts of these adjunct minor components may range anywhere from 0.001 up to 20% by weight of the formulation (i.e. composition).

The delivery system can be in any form, such as a cream, a lotion, a gel, and an aerosol foam. The amount of certain adjunct minor components used in a particular formulation varies depending on the desired form of the delivery system, as would be known by a skilled artisan. For example, the amount of thickening agent used to prepare an aerosol foam formulation is about 10 to 20% of the amount used to prepare a cream formulation. Additionally, emulsifiers are added to an aerosol foam formulation, such as, for example, laureth 4.

In another embodiment, the present invention provides a mucosal delivery system formulated to deliver a substance to, or through, a human mucous membrane without permanently disturbing the integrity of the mucous membrane. The mucous membrane is the moist tissue that lines some organs and body cavities (such as nose, mouth, lungs, rectum, stomach and vagina) and secretes mucous. The mucosal delivery system comprises the lipophilic and hydrophilic components, as described above. The particular formulations of the mucosal delivery systems are varied to accommodate the particular environment of the mucosa, as would be known by a skilled artisan.

In a preferred embodiment, the lipophilic components of the topical or mucosal delivery system form three types of particles: gas spheres, vesicles, and lipid particles. These three types of particles are within a hydrophilic phase (i.e. aqueous medium). See FIG. 1.

The gas spheres are lipid monolayers that enclose air bubbles. These monolayers are formed from the lipophilic components. Negatively charged carboxylate groups stud the outer surfaces of these gas spheres. See FIG. 2. Preferably, these gas spheres are approximately 1 μm to approximately 500 μm in diameter.

The vesicles are lipid bilayers enclosing a hydrophilic core. These bilayers are formed from the lipophilic components. Negatively charged carboxylate groups stud the inner and outer surfaces of the vesicles. See FIG. 3. The vesicles can range from approximately 0.02 μm to approximately 0.5 μm in diameter.

The lipid particles are lipid monolayers enclosing fatty acids. These monolayers are formed from the lipophilic components. See FIG. 3. The lipid particles are less than approximately 1 to approximately 150 μm in diameter. The lipid particles may be in the form of individual lipid particles, or the lipid particles may aggregate to form crystals.

The various particles of the delivery system provide microcompartments with different properties. Due to these different microcompartments, the delivery system can be used to deliver both hydrophilic and lipophilic active substances. For example, a water soluble active substance can be located in the hydrophilic core of the vesicles, or can be located in the hydrophilic phase of the system. A lipid soluble active substance can be located within the monolayer of the gas spheres, within the bilayer of the vesicles, or within the monolayer or within the core of the lipid particles. See FIG. 4.

Preferably, the delivery systems comprise three phases, i.e. a foam phase, a vesicle phase and a hydrophilic phase. The foam phase comprises the gas spheres and the lipid particles. The vesicle phase comprises the vesicles and the lipid particles. The hydrophilic phase comprises water and hydrophilic components.

In a preferred embodiment, the delivery system is produced from three portions (i.e. fractions), in particular a hydrophilic portion and two lipophilic portions. The two lipophilic portions comprise the lipophilic components as defined above. Both lipophilic portions are immersed in aqueous media. One portion is made into the foam phase. The other portion is made into the vesicle phase. The foam phase portion and the vesicle phase portion can be in a ratio from about 1:7 to about 7:1. Preferably, the foam phase portion and the vesicle phase portion are approximately equal in amount.

Preferably, the foam phase is formed by mixing the foam phase portion at about 65 to 85° C. The pH is set to the range of about 5.5 to 8.2. The mixing is performed under conditions so as to allow gas spheres to form.

Preferably, the vesicle phase is formed by gently mixing the vesicle phase portion at about 65 to 85° C. The pH is set to the range of about 5.5 to 8.2. After mixing, the vesicle phase portion is homogenized. Homogenization can be accomplished with, for example, a high pressure homogenizer or a sonicator. The pressure of the homogenizer can be set, for example, from about 10,000 to 40,000 psi. Preferably, the vesicle phase is produced under conditions which do not allow any gas to enter the formulation, such as in a vacuum.

The lipid particles, and/or lipid particle crystals, form as a by-product of the formation of the foam phase and vesicle phase. In either the foam phase or vesicle phase, up to 30% of the lipophilic components can be in the form of lipid particles and/or lipid particle crystals.

The hydrophilic phase is formed by mixing together water soluble components with water (i.e. hydrophilic portion). Examples of water soluble components include propylene glycol, glycerol, polyvinylpyrrolidone, and thickeners, e.g., xanthan gum.

The foam phase, vesicle phase and hydrophilic phases are mixed together. Preferably, an equal amount of each phase is used in the formulation.

The foam phase, vesicle phase and hydrophilic phases can be mixed together in any order. For example, the foam phase and the vesicle phase can be first mixed together, and then the resulting mixture can be mixed with the hydrophilic phase. As another example, the foam phase can be first mixed with the hydrophilic phase, and then the vesicle phase can be added.

One or more active substances can be added to the foam phase portion, the vesicle phase portion, the hydrophilic portion, or a combination of these portions.

The specific components of a formulation, and the formulation process, can be varied to obtain delivery systems which allow for different rates of the release, and degrees of penetration, of active substance(s). For example, the phase of the system in which an active substance is placed affects release and penetration rates. For instance, to enhance penetration rates of either a hydrophilic or lipophilic active substance, a major portion of the active substance is placed within the vesicle phase portion.

Another factor which affects release and penetration rates is the size of the micro-compartments. The size of the vesicles can be controlled via the formulation process. For example, during processing, as the homogenizing pressure and duration increases, the vesicle size decreases.

An additional factor which affects release and penetration rates is the type of phospholipids used in the formulation. For example, penetration can be enhanced by including a greater portion of unsaturated phospholipids within the formulation.

Also, phospholipids which include elevated levels of surface active single chain agents enhance penetration. Surface active single chain agents at about a level of 2% to 10% of the phospholipids are considered to be at an elevated level. Examples of surface active agents are lysophospholipids

An example of a phospholipid formulation comprises 95% phosphatidylcholine and 1.2% lysophosphatidylcholine. Such a formulation is sold as EPIKURON® 200 SH. A phospholipid formulation which provides enhanced penetration comprises 95% phosphatidylcholine and 3% lysophosphatidylcholine. Such a formulation is sold as EPIKURON® 200.

The concentration of free fatty acid is also an important parameter affecting penetration rates. A relatively high level of free fatty acid enhances penetration of hydrophilic active substances.

Penetration rates can also be enhanced by the addition of certain adjuvants. For example, an anionic surfactant can be added to the foam phase portion. Also, incorporation of glyceryidilaurate into the vesicle bilayers creates more flexible vesicles which can enhance penetration.

Additional factors which affect release and penetration rates include: the ratio between the different lipid components; the ratio between the foam phase, the vesicle phase and the hydrophilic phase; and the ratio between the amounts of active substances within each phase.

In one embodiment of the present invention, the lipophilic components of the delivery system form only two of the above-defined particles. That is, the formulation comprises only the gas spheres and lipid particles; or the formulation comprises only the vesicles and lipid particles.

In this embodiment, the delivery system is produced from a hydrophilic portion and a lipophilic portion. The lipophilic portion is made either into the foam phase or the vesicle phase, as described above. Preferably, the vesicle phase is produced under conditions which do not allow any gas to enter the formulation, such as in a vacuum. The foam phase or vesicle phase is mixed with the hydrophilic phase. Preferably, an equal amount of either the foam phase or vesicle phase, and the hydrophilic phase is used in the formulation.

Thus, while there have been described what are presently believed to be the preferred embodiments of the present invention, other and further embodiments, modifications, and improvements will be known to those skilled in the art, and it is intended to include all such further embodiments, modifications, and improvements and come within the true scope of the claims as set forth below.

EXAMPLES Example 1 A General Method of Making

The phospholipid, cholesterol, palmitic acid and ceramide components are mixed together with water, and agitated at a temperature of 70-80° C. The following additional components are added: mevalonic acid lactone, 25-hydroxycholecalciferol, propylene glycol, glycerine, PVP, TEA added along with water, and sodium hydroxide. Sodium hydroxide is added to adjust viscosity and stabilize the formulation. Water is then added, and the formulation is agitated well. The formulation is then cooled down.

An active substance can be dissolved in both the lipid phase and/or the water phase, depending on the solubility and concentration of the active substance.

Example 2 Formulation of a Preferred Embodiment of the Topical Delivery System

(An active ingredient is excluded from this formulation.)

Component Total amount Water 79.5% of formulation  Epikuron 200SH 3.5% of formulation Palmitic acid 1.5% of formulation Cholesterol 1.5% of formulation Mevalonic acid 0.01% of formulation  Triethanolamine 0.5% of formulation Phenonip 0.4% of formulation Xanthan gum 2.0% of formulation Skinflux 2.0% of formulation 25-hydroxycholecalciferol 0.0015% of formulation   Propylene glycol 4.0% of formulation Glycerol 3.0% of formulation Polyvinylpyrrolidone 2.0% of formulation Epikuron 200SH are hydrogenated lecithins, i.e. phosphatidylcholine (PC). “Skinflux” is a blend product obtainable from Degussa Goldschmidt which contains: Ceramide 1, 3, 6II; Phytosphingosine; Cholesterol; Sodium Lauroyl Lactylate; Carbomer; and Xanthan Gum. Mevalonic acid lactone is a lipid precursor for cholesterol/fatty acids. 25-Hydroxycholecalciferol is a lipid precursor for ceramides Xanthan Gum is a thickener (polysaccharide). PHENONIP ® is a preservative and a blend of parabens.

Three fractions, a vesicle fraction, a foam fraction and a hydrophilic fraction, are first prepared separately, as described below. Each fraction weighs 3.3 kg. Then the three fractions are mixed together. The following tables show the percent amount of each component contributed by each fraction to the final formulation. Thus, for each component, the sum of the percent amounts of all the fractions is 100%.

1: Vesicle Fraction

Percent Amount in Final Component Formulation Water 33% of total water Hydrogenated lecithins 50% of total amount Palmitic acid 50% of total amount Cholesterol 50% of total amount Mevalonic acid 50% of total amount Triethanol amine 50% of total amount Preservative (e.g., Paraben mixture) 50% of total amount Xanthan gum 15% of total amount Skinflux 33% of total amount 25-hydroxycholecalciferol 50% of total amount 5M sodium hydroxide 1.3 ml per 1000 grams of water The “Percent Amount in Final Formulation” indicates the percentage of each component which is contributed by the vesicle fraction to the final formulation.

In forming the vesicle fraction, the components are mixed and heated to the temperature range of 65 to 85° C. while gently stirring. The pH is set to the range of 5.5 to 8.2 by the use of sodium hydroxide. The resulting mixture is then homogenized. Homogenization can be accomplished by, for example, a homogenizer set at a high pressure (e.g. 10,000 to 40,000 psi); or by a sonicator. The size of the vesicles is partially dependent upon how long the resulting mixture is agitated. For example, to obtain an average vesicle size of 0.140 μm, the resulting mixture is agitated for 60 minutes at about 70° C. The mixture is then allowed to cool to below 40° C.

2: Foam Fraction

Percent Amount in Final Component Formulation Water  33% of total water Hydrogenated lecithins  50% of total amount Palmitic acid  50% of total amount Cholesterol  50% of total amount Mevalonic acid  50% of total amount Triethanol amine  50% of total amount Preservative (e.g. a paraben mixture)  50% of total amount Xanthan gum 7.5% of total amount Skinflux  33% of total amount 25-hydroxycholecalciferol  50% of total amount 5M sodium hydroxide 1.3 ml per 1000 g of water The “Percent Amount in Final Formulation” indicates the percentage of each component which is contributed by the foam fraction to the final formulation.

In forming the foam fraction, the components are mixed and heated to the temperature range of 65 to 85° C. while stirring. The pH is set to the range of 5.5 to 8.2 by the use of sodium hydroxide. The composition is mixed vigorously for 1 minute. Mixing can be done with ULTRATURRAX® from IKA Werke, Janke & Kunkel GmbH & Co KG (Staufen, Germany). The composition is then allowed to cool to below 40° C.

3: Hydrophilic Fraction

Percent Amount in Final Component Formulation Water   34% of total water Propylene glycol  100% of total amount Glycerol  100% of total amount Polyvinylpyrrolidone  100% of total amount Xanthan gum 77.5% of total amount Skinflux   34% of total amount 5M sodium hydroxide 3.0 ml per 1000 g of water The “Percent Amount in Final Formulation” indicates the percentage of each component which is contributed by the hydrophilic fraction to the final formulation.

In forming the hydrophilic fraction, the components are mixed and heated to the temperature range of 65 to 85° C. while stirring. The pH is set to the range of 5.5 to 8.2 by use of sodium hydroxide. Once homogeneous, the composition is then allowed to cool to below 40° C.

In forming the final formulation, after all the fractions are cooled down (below 40° C.), the three fractions are mixed together in any order. For example, the foam fraction is added to the vesicle fraction and gently mixed. Then the hydrophilic fraction is added. The resulting mixture is gently blended for several minutes to obtain a homogeneous solution.

The delivery system of this example is in the form of a cream. In order to produce a delivery system in an aerosol foam form, the total amount of xanthan gum in the final formulation is reduced from 2% to about 0.3%. Additionally, an emulsifier is added, such as laureth 4. Preferably, the emulsifier makes up about 0.7% of the final formulation.

Example 3 Formulation with Lidocaine as an Active Ingredient

An example of a 48 kg batch of a formulation of the delivery system follows. The three fractions used to prepare this formulation each contain 16 kg.

INCI Name Trade Name Supplier CAS Amount Hydrogenated Epikuron 200 SH Degussa 1.7 kg Lecithines Goldschmidt Cholesterol Vendico 57-88-5 0.8 kg Palmitic acid Karlshamn 57-10-3 0.8 kg Ceramide 1, 3, 6II, Skin Flux Degussa 1.0 kg Phytosphingosine, Goldschmidt Cholesterol, Sodium Lauroyl Lactylate, Carbomer, Xanthan Gum. Mevalonic acid Sigma Aldrich 674-26-0 4.8 g  lactone 25-Hydroxy- Solvay 19356-17-3 0.72 kg  cholecalciferol Propylene glycol MB-Sveda 57-55-6 2.0 kg Glycerin, 99.5% Vendico 56-81-5 1.5 kg Polyvinylpyrrolidone Apoteket 9003-39-8 1.0 kg Xanthan gum Sigma Aldrich 11138-66-2 1.0 kg Triethanolamine, MB-Sveda 102-71-6 0.3 kg 85% Phenonip Vendico 0.2 kg Chemical Lidocain USP-grade Apoteket 2.4 kg Purified Up to Water  48 kg

Example 4 Measurement of Skin Barrier Restoration

In the present context enhancing skin barrier restoration can be measured by tape and/or acetone striping of stratum corneum skin lipid content before, during and after a treatment period with the present invention and other systems. Then HPLC analysis of skin lipid content of stratum corneum is conducted. 

1. A water-based topical delivery system for an active substance, capable of enhancing skin barrier restoration in the stratum corneum comprising water; fatty acids; cholesterol; and a ceramide/phospholipid portion.
 2. A delivery system according to claim 1 wherein the ratio of ceramide/phospholipid portion:cholesterol:fatty acid is approximately between 2:1:1 and 2.35:1:1.
 3. A delivery system according to claim 1 further comprising at least one skin lipid precursor.
 4. A delivery system according to claim 3 wherein the fatty acid is between 0.5-10%; the cholesterol is between 0.5-10%; the lipid precursors are between 0.000001-10%; and the ceramide/phospholipid portion is between 0.005-20%.
 5. A delivery system according to claim 1 wherein the fatty acid comprises ten to twenty-four carbon atoms.
 6. A delivery system according to claim 5 wherein the fatty acid comprises sixteen to eighteen carbon atoms.
 7. A delivery system according to claim 1 wherein the fatty acid is lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, oleic acid, palmitoleic acid, linoleic acid, linolenic acid, arachidonic acid, precursors thereof, and/or unsaturated derivatives thereof, and/or mixtures thereof.
 8. A delivery system according to claim 1, wherein said fatty acid is selected from a group consisting of linoleic acid, γ-linolenic acid, homo-γ-linolenic acid, columbinic acid, eicosa-(n-6,9,13)-trienoic acid, arachidonic acid, timnodonic acid, hexaenoic acid and mixtures thereof.
 9. A delivery system according to claim 6 wherein the ceramide is ceramide 1, ceramide 3, ceramide 4, ceramide 5, ceramide 6A, a cerebroside, ceramide 6B, a pseudoceramide, a neoceramide, or mixtures thereof.
 10. A delivery system according to claim 9 wherein the pseudoceramide is N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)hexadecanamide; N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)propanamide; N-(2-hydroxyhexadecyl)-N-(2-hydroxyethyl)butanamide; N-(2-hydroxyhexadecyl)-N-(2-hydroxyethyl)heptanamide; N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)ethanamide; N-(2-hydroxyoctadecyl)-N-(2-O-glucopyranosyl)ethylpentanamide; N-(2-hydroxydodecyl)-N-(2-hydroxyethyl)hexanamide; N-(2-hydroxydodecyl)-N-(2-hydroxyethyl)-2butylhexanamide; N-(2-hydroxyhexadecyl)-N-(2-hydroxyethyl)ethanamide; N-(2-hydroxydodecyl)-N-(2-hydroxyethyl)-2-hydroxyhexanamide; N-(2-hydroxytetraadecyl)-N-(2-hydroxyethyl)propanamide; N-(2-hydroxyhexadecyl)-N-(2-sulfoethyl)hexadecanamide; N-(2-hydroxyoctadecyl)-N-(2-phosphoethyl)butanamide; N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)-2-hydroxypropanamide; N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)hexadecanamide; N-(2-hydroxy-3-nonanyloxypropyl)-N-(2-hydroxyethyl)propanamide; N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)-2-hydroxypropanamide; N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-hydroxyethyl)hexadecanamide; N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)butanamide; N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-hydroxyethyl)ethanamide; N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-sulfohydroxyethyl)decanamide; N-(2-hydroxy-3-decyloxypropyl)-N-(2-hydroxyethyl)hexanamide; N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)hexadecanamide; N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)butanamide; N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)co-o-linoleoyldocosanamide; N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)propanamide; N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-hydroxyethyl)-2-methylpropanamide; N-(2-hydroxy-3-tetraadecyloxypropyl)-N-(2-hydroxyethyl)ethanamide; N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)heptanamide; N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-phosphoethyl)hexadecanamide; N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)propanamide; N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-)-glucopyranosyl)ethyl-2-hydroxypropanamide; or N-(2-hydroxy-3-octyloxypropyl)-N-(2-hydroxyethyl)pentanamide.
 11. A delivery system according to claim 9 wherein the neoceramide is: N-(2,3-dihydroxypropyl)-N-(hexadecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(tetradecyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(hexadecyl)-2-hydroxypropanamide; N-(2,3-dihydroxypropyl)-N-(octadecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(2-ethylhexadecyl)hexanamide; N-(2,3-dihydroxypropyl)-N-(hexadecyl)-2-hydroxyoctanamide; N-(2,3-dihydroxypropyl)-N-(3-methylhexadecyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(dodecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(hexadecyl)-2-hydroxyhexanamide; N-(2-hydroxy-3-O-glucopyranosylpropyl)-N-(hexadecyl)octanamide; N-(2-hydroxy-3-phosphopropyl)-N-(octadecyl)ethanamide; N-(2-hydroxy-3-sulfopropyl)-N-(hexadecyl)butanamide; N-(2-hydroxy-3-O-glucopyranosylpropyl)-N-(hexadecyl)decanamide; N-(2,3-dihydroxypropyl)-N-(heptadecyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(3-methylhexadecyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(heptadecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(6-dodecenyl)hexadecan-amide; N-(2,3-dihydroxypropyl)-N-(2-methylhexadecyl)-2-hydroxy-ethanamide; N-(2,3-dihydroxypropyl)-N-(octadecyl)2-hydroxypropan-amide; N-(2-hydroxy-3-O-glucopyranosylpropyl)-N-(heptadecyl)-ethanamide; N-(2-hydroxy-3-sulfopropyl)-N-(dodecyl)heptanamide; N-(2,3-dihydroxypropyl)-N-(tetradecyl)-4-hydroxybutan-amide; N-(2,3-dihydroxypropyl)-N-(octadecyl)-(t)-O-linoleoyl-docosanamide; N-(2,3-dihydroxypropyl)-N-(linoleyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(oleyl)-2-hydroxy-heptan-amide; N-(2,3-dihydroxypropyl)-N-iyiodecyl)-(t)-O-linoleoyldocosanamide; N-(2,3-dihydroxypropyl)-N-(octadecyl)-3-hydroxybutanamide; N-(2-phospho-3hydroxypropyl)-N-(heptadecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(2-methylheptadecyl)propanamide; N-(2,3-dihydroxypropyl)-N-(3-ethylheptadecyl)butanamide; N-(2-sulfo-3-hydroxypropyl)-N-(1-octadecyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(octadecyl)propanamide; N-(2,3-dihydroxypropyl)-N-(dodecyl)decanamide; N-(2,3-dihydroxypropyl)-N-(3-ethyldodecyl)butanamide; N-(2-O-glucopyranosyl-3-hydroxy propyl)-N-(heptadecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(oleyl)-2-hydroxypropanamide; N-(2,3-dihydroxypropyl)-N-(linoleyl)-2-hydroxyheptanamide; N-(2,3-dihydroxypropyl)-N-(dodecyl)-2-hydroxyoctanamide; N-(2,3-dihydroxypropyl)-N(hexadecyl)-2-methylheptanamide; N-(2,3-dihydroxypropyl)-N-(octadecyl)-2-hydroxypentanamide; N-(2,3-dihydroxypropyl)-N-(2-methylhexadecyl)-2-hydroxyheptanamide; N-(2,3-dihydroxypropyl)-N-(linoleyl)-2-hydroxypropanamide; or N-(2; 3-dihydroxypropyl)-N-(tetradecyl)ethanamide.
 12. A delivery system according to claim 1, wherein said phospholipid is selected from a group consisting of phosphatidylcholine, DSPC 18, phosphatidic acid, inositol phosphate, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine and mixtures thereof.
 13. A delivery system according to claim 12, wherein said phospholipid comprises at least one lysophospholipid.
 14. A delivery system according to claim 13 wherein the lysophospholipid is selected from the group consisting of monopalmitoylphosphatidylcholine (MPPC), lysophosphatidylcholines, lysophosphatidylglycerols, lysophosphatidylethanolamines, lysophosphatidylinositols, lysophosphatidylserines, lysophosphatidic acid, and mixtures thereof.
 15. A delivery system according to claim 3 wherein the lipid precursor comprises mevalonic acid or 25-hydroxycholecalciferol.
 16. A delivery system according to claim 3 wherein the lipid precursor comprises deoxyacetein cimifugoside, adapalene, adenosine, aloe derived lectins, 3-aminopropyl dihydrogen phosphate, anise extracts, ascorbic acid and derivatives thereof, ascorbyl palmitate, asiatic acid, benzoic acid derivatives, biotin, butanoyl betulinic acid, cathecholamines, coenzyme Q10, dehydrocholesterol, dehydroascorbic acid and derivatives thereof, estrogen and derivatives, eythrobic acid, genistein, lipoic acid, 4-methoxy salicylic acid, N-acetyl cysteine, panthetine, pregnenolone and derivatives, retinal, retinoates, retinal, retinyl acetate, retinyl glucuronate, retinyl linoleate, retinyl palmitate, retinyl proprionate, phytosphingosine, or sphingosine.
 17. A delivery system according to claim 1 further comprising triethanolamine.
 18. A delivery system according to claim 1, wherein the water content exceeds 50%.
 19. A delivery system according to claim 1, wherein the water content exceeds 75%.
 20. A delivery system according to claim 1, wherein the water content exceeds 79%.
 21. A delivery system according to claim 1, wherein the water content exceeds 90%.
 22. A delivery system according to claim 3, wherein the combined content of a fatty acid, cholesterol, a ceramide/phospholipid portion, and a skin lipid precursor in said system is between about 2-20%.
 23. A delivery system according to claim 3, wherein the combined content of a fatty acid, cholesterol, a ceramide/phospholipid portion, and a skin lipid precursor in said system is between about 5-20%.
 24. A delivery system according to claim 3, wherein the combined content of a fatty acid, cholesterol, a ceramide/phospholipid portion, and a skin lipid precursor in said system is between about 5-15%.
 25. A delivery system according to claim 3, wherein the combined content of a fatty acid, cholesterol, a ceramide/phospholipid portion, and a skin lipid precursor in said system is between about 6-13%.
 26. A delivery system according to claim 3, comprising a combination of: Fatty Acid 0.5-10% Phospholipid 0.5-10% Cholesterol 0.5-7%  Lipid precursor 0.000001-10%    Ceramide 0.005%-7%.    


27. A delivery system according to claim 26 wherein the lipid precursor is mevalonic acid.
 28. A delivery system according to claim 26, further comprising Glycerine 0-5% Propylene glycol  0-48% PVP (M weight 40.000) 0-5% TEA  0-3%.


29. A delivery system according to claim 26, further comprising 25-Hydroxycholecalciferol 0.015%  Acylceramides 0.025%.


30. A delivery system according to claim 26, wherein the lipid precursor comprises 0.01% of Mevalonic acid, 0.0015% 25-Hydroxycholecalciferol, or a combination of Mevalonic acid, and 25-Hydroxycholecalciferol.
 31. A delivery system according to claim 3, wherein said skin barrier restoration is enhanced by in situ promotion of cholesterol synthesis in the stratum corneum.
 32. A delivery system according to claim 3, wherein said skin barrier restoration is enhanced by in situ promotion of ceramide synthesis in the stratum corneum.
 33. A delivery system according to claim 3, wherein said skin barrier restoration is enhanced by in situ promotion of sphingolipid synthesis in the stratum corneum.
 34. A delivery system according to claim 1, wherein said system further comprises one or more therapeutically active substances selected from the group consisting of peptides, proteins, sunscreens, tanning agents, skin anti-wrinkling agents, anti-dandruff agents, anti-acne agents, hair growth stimulants, hormones, vaccines, nicotine, interferon, pain killers, vitamins; and substances which treat eczema, dry skin, itchy skin, fungal infections, acne, skin cancer, hair loss, louse infections, psoriasis, and skin lesions.
 35. A delivery system according to claim 3, wherein the lipids of said system blend with the lipids present in the cornea stratum, resulting in a temporary and reversible atrophy in the lipid bilayer, thereby enhancing possibility for penetration of therapeutic substances delivered by the system.
 36. A delivery system according to claim 3, wherein the system does not comprise alcohol.
 37. A delivery system according to claim 36, wherein the alcohol is ethanol.
 38. A delivery system according to claim 3, wherein the system comprises less than 10% alcohol.
 39. A delivery system according to claim 38 wherein the alcohol is ethanol.
 40. A topical delivery system for an active substance comprising water and lipophilic components, wherein the lipophilic components comprise fatty acids, cholesterol, and a ceramide/phospholipid portion, and wherein the lipophilic components are in the form of lipid particles, and gas spheres or vesicles.
 41. A topical delivery system according to claim 40 further comprising at least one skin lipid precursor.
 42. A topical delivery system for an active substance comprising water and lipophilic components, wherein the lipophilic components comprise fatty acids, cholesterol, and a ceramide/phospholipid portion, and wherein the lipophilic components are in the form of lipid particles, gas spheres and vesicles.
 43. A topical delivery system according to claim 42 further comprising at least one skin lipid precursor.
 44. A topical delivery system according to claim 40 wherein the diameter of the gas spheres is approximately 1 μm to 500 μm.
 45. A topical delivery system according to claim 40 wherein the diameter of the vesicles is approximately 0.02 μm to 0.5 μm.
 46. A topical delivery system according to claim 40 wherein the diameter of the lipid particles is approximately less than 1 μm to 150 μm.
 47. A delivery system according to claim 41 wherein the fatty acid is between 0.5-10%; the cholesterol is between 0.5-10%; the lipid precursors are between 0.000001-10%; and the ceramide/phospholipid portion is between 0.005-20%.
 48. A delivery system according to claim 40 wherein the fatty acid comprises ten to twenty-four carbon atoms.
 49. A delivery system according to claim 48 wherein the fatty acid comprises sixteen to eighteen carbon atoms.
 50. A delivery system according to claim 40 wherein the fatty acid is lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, oleic acid, palmitoleic acid, linoleic acid, linolenic acid, arachidonic acid, precursors thereof, and/or unsaturated derivatives thereof, and/or mixtures thereof.
 51. A delivery system according to claim 40, wherein said fatty acid is selected from a group consisting of linoleic acid, γ-linolenic acid, homo-γ-linolenic acid, columbinic acid, eicosa-(n-6,9,13)-trienoic acid, arachidonic acid, timnodonic acid, hexaenoic acid and mixtures thereof.
 52. A delivery system according to claim 43 wherein the ceramide is ceramide 1, ceramide 3, ceramide 4, ceramide 5, ceramide 6A, a cerebroside, ceramide 6B, a pseudoceramide, a neoceramide, or mixtures thereof.
 53. A delivery system according to claim 52 wherein the pseudoceramide is N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)hexadecanamide; N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)propanamide; N-(2-hydroxyhexadecyl)-N-(2-hydroxyethyl)butanamide; N-(2-hydroxyhexadecyl)-N-(2-hydroxyethyl)heptanamide; N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)ethanamide; N-(2-hydroxyoctadecyl)-N-(2-O-glucopyranosyl)ethylpentanamide; N-(2-hydroxydodecyl)-N-(2-hydroxyethyl)hexanamide; N-(2-hydroxydodecyl)-N-(2-hydroxyethyl)-2butylhexanamide; N-(2-hydroxyhexadecyl)-N-(2-hydroxyethyl)ethanamide; N-(2-hydroxydodecyl)-N-(2-hydroxyethyl)-2-hydroxyhexanamide; N-(2-hydroxytetraadecyl)-N-(2-hydroxyethyl)propanamide; N-(2-hydroxyhexadecyl)-N-(2-sulfoethyl)hexadecanamide; N-(2-hydroxyoctadecyl)-N-(2-phosphoethyl)butanamide; N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)-2-hydroxypropanamide; N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)hexadecanamide; N-(2-hydroxy-3-nonanyloxypropyl)-N-(2-hydroxyethyl)propanamide; N-(2-hydroxyoctadecyl)-N-(2-hydroxyethyl)-2-hydroxypropanamide; N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-hydroxyethyl)hexadecanamide; N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)butanamide; N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-hydroxyethyl)ethanamide; N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-sulfohydroxyethyl)decanamide; N-(2-hydroxy-3-decyloxypropyl)-N-(2-hydroxyethyl)hexanamide; N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)hexadecanamide; N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)butanamide; N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-hydroxyethyl)co-o-linoleoyldocosanamide; N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)propanamide; N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-hydroxyethyl)-2-methylpropanamide; N-(2-hydroxy-3-tetraadecyloxypropyl)-N-(2-hydroxyethyl)ethanamide; N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)heptanamide; N-(2-hydroxy-3-hexadecyloxypropyl)-N-(2-phosphoethyl)hexadecanamide; N-(2-hydroxy-3-dodecyloxypropyl)-N-(2-hydroxyethyl)propanamide; N-(2-hydroxy-3-octadecyloxypropyl)-N-(2-)-glucopyranosyl)ethyl-2-hydroxypropanamide; or N-(2-hydroxy-3-octyloxypropyl)-N-(2-hydroxyethyl)pentanamide.
 54. A delivery system according to claim 52 wherein the neoceramide is: N-(2,3-dihydroxypropyl)-N-(hexadecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(tetradecyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(hexadecyl)-2-hydroxypropanamide; N-(2,3-dihydroxypropyl)-N-(octadecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(2-ethylhexadecyl)hexanamide; N-(2,3-dihydroxypropyl)-N-(hexadecyl)-2-hydroxyoctanamide; N-(2,3-dihydroxypropyl)-N-(3-methylhexadecyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(dodecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(hexadecyl)-2-hydroxyhexanamide; N-(2-hydroxy-3-O-glucopyranosylpropyl)-N-(hexadecyl)octanamide; N-(2-hydroxy-3-phosphopropyl)-N-(octadecyl)ethanamide; N-(2-hydroxy-3-sulfopropyl)-N-(hexadecyl)butanamide; N-(2-hydroxy-3-O-glucopyranosylpropyl)-N-(hexadecyl)decanamide; N-(2,3-dihydroxypropyl)-N-(heptadecyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(3-methylhexadecyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(heptadecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(6-dodecenyl)hexadecan-amide; N-(2,3-dihydroxypropyl)-N-(2-methylhexadecyl)-2-hydroxy-ethanamide; N-(2,3-dihydroxypropyl)-N-(octadecyl)-2-hydroxypropan-amide; N-(2-hydroxy-3-O-glucopyranosylpropyl)-N-(heptadecyl)-ethanamide; N-(2-hydroxy-3-sulfopropyl)-N-(dodecyl)heptanamide; N-(2,3-dihydroxypropyl)-N-(tetradecyl)-4-hydroxybutan-amide; N-(2,3-dihydroxypropyl)-N-(octadecyl)-(t)-O-linoleoyl-docosanamide; N-(2,3-dihydroxypropyl)-N-(linoleyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(oleyl)-2-hydroxy-heptan-amide; N-(2,3-dihydroxypropyl)-N-iyiodecyl)-(t)-O-linoleoyldocosanamide; N-(2,3-dihydroxypropyl)-N-(octadecyl)-3-hydroxybutanamide; N-(2-phospho-3hydroxypropyl)-N-(heptadecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(2-methylheptadecyl)propanamide; N-(2,3-dihydroxypropyl)-N-(3-ethylheptadecyl)butanamide; N-(2-sulfo-3-hydroxypropyl)-N-(1-octadecyl)ethanamide; N-(2,3-dihydroxypropyl)-N-(octadecyl)propanamide; N-(2,3-dihydroxypropyl)-N-(dodecyl)decanamide; N-(2,3-dihydroxypropyl)-N-(3-ethyldodecyl)butanamide; N-(2-O-glucopyranosyl-3-hydroxy propyl)-N-(heptadecyl)butanamide; N-(2,3-dihydroxypropyl)-N-(oleyl)-2-hydroxypropanamide; N-(2,3-dihydroxypropyl)-N-(linoleyl)-2-hydroxyheptanamide; N-(2,3-dihydroxypropyl)-N-(dodecyl)-2-hydroxyoctanamide; N-(2,3-dihydroxypropyl)-N(hexadecyl)-2-methylheptanamide; N-(2,3-dihydroxypropyl)-N-(octadecyl)-2-hydroxypentanamide; N-(2,3-dihydroxypropyl)-N-(2-methylhexadecyl)-2-hydroxyheptanamide; N-(2,3-dihydroxypropyl)-N-(linoleyl)-2-hydroxypropanamide; or N-(2; 3-dihydroxypropyl)-N-(tetradecyl)ethanamide.
 55. A delivery system according to claim 40, wherein said phospholipid is selected from a group consisting of phosphatidylcholine, DSPC 18, phosphatidic acid, inositol phosphate, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine and mixtures thereof.
 56. A delivery system according to claim 55, wherein the phospholipids comprises at least one lysophospholipid.
 57. A delivery system according to claim 56 wherein the lysophospholipid is selected from the group consisting of monopalmitoylphosphatidylcholine (WPC), lysophosphatidylcholines, lysophosphatidylglycerols, lysophosphatidylethanolamines, lysophosphatidylinositols, lysophosphatidylserines, lysophosphatidic acid, and mixtures thereof.
 58. A delivery system according to claim 41 wherein the lipid precursor comprises mevalonic acid or 25-hydroxycholecalciferol.
 59. A delivery system according to claim 41 wherein the lipid precursor comprises deoxyacetein cimifugoside, adapalene, adenosine, aloe derived lectins, 3-aminopropyl dihydrogen phosphate, anise extracts, ascorbic acid and derivatives thereof, ascorbyl palmitate, asiatic acid, benzoic acid derivatives, biotin, butanoyl betulinic acid, cathecholamines, coenzyme Q10, dehydrocholesterol, dehydroascorbic acid and derivatives thereof, estrogen and derivatives, eythrobic acid, genistein, lipoic acid, 4-methoxy salicylic acid, N-acetyl cysteine, panthetine, pregnenolone and derivatives, retinal, retinoates, retinal, retinyl acetate, retinyl glucuronate, retinyl linoleate, retinyl palmitate, retinyl proprionate, phytosphingosine, or sphingosine.
 60. A delivery system according to claim 40 further comprising triethanolamine.
 61. A delivery system according to claim 40, wherein the water content exceeds 50%.
 62. A delivery system according to claim 40, wherein the water content exceeds 75%.
 63. A delivery system according to claim 40, wherein the water content exceeds 79%.
 64. A delivery system according to claim 40, wherein the water content exceeds 90%.
 65. A delivery system according to claim 40, wherein the combined content of a fatty acid, cholesterol, a ceramide/phospholipid portion, and a skin lipid precursor in said system is between about 2-20%.
 66. A delivery system according to claim 41, wherein the combined content of a fatty acid, cholesterol, a ceramide/phospholipid portion, and a skin lipid precursor in said system is between about 5-20%.
 67. A delivery system according to claim 41, wherein the combined content of a fatty acid, cholesterol, a ceramide/phospholipid portion, and a skin lipid precursor in said system is between about 5-15%.
 68. A delivery system according to claim 41, wherein the combined content of a fatty acid, cholesterol, a ceramide/phospholipid portion, and a skin lipid precursor in said system is between about 6-13%.
 69. A delivery system according to claim 41, comprising a combination of: Fatty Acid 0.5-10% Phospholipid 0.5-10% Cholesterol 0.5-7%  Lipid precursor 0.000001-10%    Ceramide 0.005%-7%.    


70. A delivery system according to claim 69 wherein the lipid precursor is mevalonic acid.
 71. A delivery system according to claim 69, further comprising Glycerine 0-5% Propylene glycol  0-48% PVP (M weight 40.000) 0-5% TEA  0-3%.


72. A delivery system according to claim 69, wherein the lipid precursor comprises 0.01% of Mevalonic acid; 0.0015% of 25-Hydroxycholecalciferol or a mixture of both.
 73. A delivery system according to claim 41, wherein said skin barrier restoration is enhanced by in situ promotion of cholesterol synthesis in the stratum corneum.
 74. A delivery system according to claim 41, wherein said skin barrier restoration is enhanced by in situ promotion of ceramide synthesis in the stratum corneum.
 75. A delivery system according to claim 41, wherein said skin barrier restoration is enhanced by in situ promotion of sphingolipid synthesis in the stratum corneum.
 76. A delivery system according to claim 40, wherein said system further comprises one or more therapeutically active substances selected from the group consisting of: peptides, proteins, sunscreens, tanning agents, skin anti-wrinkling agents, anti-dandruff agents, anti-acne agents, hair growth stimulants, hormones, vaccines, nicotine, interferon, pain killers, vitamins; and substances which treat eczema, dry skin, itchy skin, fungal infections, acne, skin cancer, hair loss, louse infections, psoriasis, and skin lesions.
 77. A delivery system according to claim 40, wherein the system does not comprise alcohol.
 78. A delivery system according to claim 77, wherein the alcohol is ethanol.
 79. A delivery system according to claim 40, wherein the system comprises less than 10% alcohol.
 80. A delivery system according to claim 79 wherein the alcohol is ethanol. 